Circuit interrupter construction



Dec. 17, 1957 v s. 1. LINDELL 2,816,984

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Jgzzraiffazddd United States Patent CIRCUIT INTERRUPTER CONSTRUCTIONSigurd I. Lindell, Chicago, Ill., assignor to S & C Electric Company,Chicago, 111., a corporation of Delaware Original application February24, 1954, Serial No. 412,182. Divided and this application May 27, 1957,Serial'No. 661,756

7 Claims. (Cl. 200114) This invention relates, generally, to highvoltage circuit interrupters, and it has particular relation to theconstruction of auxiliary circuit interrupters used in conjunction withhigh voltage isolating devices, such as disconnecting fuses,disconnecting switches and the like, for opening them without externalarcing while they are carrying line current. This invention constitutesan improvement over the constructions disclosed in Lindell Patent Nos.2,671,142 and 2,671,145, both dated March 2, 1954, and assigned to theassignee of this application. This application is a division ofapplication Serial No. 412,182, filed February 24, 1954.

Among the objects of this invention are: To flexibly mount the auxiliarycircuit interrupter on a support that is adapted to be carried by a liveline stick for manipulation into and out of operative engagement withthe separable energized current carrying terminals or contacts of thecircuit isolating device; to provide a rigid mechanical connectionbetween the live line stick and the movable contact or terminal of thecircuit isolating device to permit positive control thereof for swingingit either to the open position or reclosing it should the operatorchange his mind and decide not to complete the opening of the circuit;to permit relative movement of the interrupter unit with respect to theaxis of the live line stick as the pin or stud of the stick follows thepath taken by the movable contact on the circuit isolating device; toposition an eye on the interrupter for engagement with a horn or stud onthe stationary line terminal or contact of the circuit isolating deviceand incline the same with respect to the longitudinal axis of the liveline stick in order to facilitate engagement with the horn or stud; toemploy spring biased universal joint means for positioning theinterrupter to facilitate engagement with the born or stud by the eyeand then permit moving of the live line stick sidewise to cause a pincarried thereby to engage a ring, or like device, on a movable contactor terminal of the load isolating device; to hold the flexibly mountedinterrupter in fixed position with respect to the live line stick whenthe interrupter is not to be used for interrupting the circuit; toenclose the major .portion of the interrupter within an insulatinghousing; to make connection with one of the separable contacts of theinterrupter by a rigid conducting arm extending into the insulatinghousing; to provide for removing as a unit the circuit interruptingparts of the interrupter most likely to be eroded or consumed followingrepeated circuit opening operations; to control the position of the aredrawn on separation of the contacts in the auxiliary circuit interrupterin order to prevent it from impinging on contact surfaces or corners ofcontact fingers likely to be damaged; to provide for the ready escape ofthe products of the are past one of the contacts; to mount a set ofseparable contacts for conjoint movement within the housing during whicha spring is stressed and then releasing one of the contacts to move witha snap action away from the other to draw an arc and interrupt thecircuit; to extinguish the arc'thus drawn; to limit the separation ofthe contacts; and to coordinate the separation of the contacts as biasedby the spring with the separation of the terminals or contacts of thecircuit iso1atice ing device whereby there is no likelihood of an arerestriking between these terminals or contacts.

Other objects of this invention will, in part, be obvious and in partappear hereinafter.

This invention is disclosed in the embodiment thereof shown in theaccompanying drawings and it comprises,

the features of construction, combination of elements and arrangement ofparts which will be exemplified in the construction hereinafter setforth and the scope of the application of which will be indicated in theappended claims.

For a more complete understanding of the nature and scope of thisinvention, reference can be had to the following detailed description,taken together with the accompanying drawings, in which:

Figure 1 is a perspective view of a circuit isolating device, such as adisconnecting fuse showing how the auxiliary circuit interrupter of thepresent invention can be applied thereto, the particular circuitisolating device being that disclosed in Lindell Patent No. 2,745,923,issued May 15, 1956, and assigned to the assignee of this application;

Figure 2 is an elevational view showing how the auxiliary circuitinterrupter is mounted on a live line tool for relative movement inopposite directions with respect to its longitudinal axis in a planeparallel to the plane containing the same;

Figure 3 is an elevational view showing how the auxiliary circuitinterrupter can be held in fixed position with respect to the live linestick when it is desired to employ the latter solely for manipulating adisconnecting fuse or disconnecting switch blade;

Figure 4 is an elevational view showing the first step employed inapplying the auxiliary circuit interrupter to a circuit isolatingdevice;

Figure 5 is an elevational view showing the second step employed inapplying the auxiliary circuit interrupter to a circuit isolatingdevice, this view showing the auxiliary circuit interrupter positionedso as to provide a shunt circuit between the separable energized currentcarrying terminals or contacts of the circuit isolating device;

Figures 6 and 6A taken together provide a longitudinal sectional view,at an enlarged scale, showing the internal details of construction of anauxiliary circuit interrupter embodying this invention;

Figure 7 shows a longitudinal sectional view of the auxiliary circuitinterrupter at a reduced scale and illustrates how it is mounted on thelive line stick, the con nections being the same as described for Figure5;

Figure 8 is a view, similar to Figure 7, showing the auxiliary circuitinterrupter in extended position with the latch for holding theseparable contacts in engagement in tripped position and just before anymovement of these contacts takes place;

Figure 9 is a view, similar to Figure 8, but showing the contacts in theauxiliary circuit interrupter separated with one contact being withdrawninto the bore of the liner of arc extinguishing material;

Figure 10 is a view, partly in elevation and partly in section, showingthe auxiliary circuit interrupter extended to its fullest extent, thesection being taken at right angles to the section shown in Figure 9;

Figure 11 is a sectional View taken generally along the line 1111 ofFigure 6A;

Figure 12 is a sectional view taken generally along the line 1212 ofFigure 6A and looking in the direction opposite to the direction inwhich Figure 11 is taken;

Figure 13 is a view, in side elevation, of the liner of arcextinguishing material; and

Figure 14 is a view, partly in side elevation and partly in section, ofthe inner contact sleeve.

Referring now particularly to Figure 1 of the drawings, it will beobserved that the reference character designates, generally, a circuitisolating device of the disconnecting fuse type. As pointed outhereinbefore, the details of construction of the-circuit isolatingdevice 10 are set forth in Lindell Patent No. 2,745,923, issued May 15,1956. Accordingly, only a general description of this device will be setforth here. While particular reference is made to a disconnecting fusedevice, it will be understood that the present invention can be employedwhere the fuse tube of the disconnecting fuse is replaced by a metallicconducting tube or it can be used in conjunction with a disconnectingswitch that is modified suitably for adaptation to be used inconjunction with the auxiliary circuit interrupter mounted on a liveline stick as described hereinafter.

The circuit isolating device or disconnecting fuse 10 includes aninsulator 11. which is arranged to be stationarily mounted on a crossarm or the likeand has a lower terminal contact member 12 carryingaconnector 13 for connection to a line terminal. Pivoted at 14 on thelower terminal contact member 12 is a lower current carrying member 15that is positioned at the lower end of a fuse tube 16. At its upper endthe fuse tube 16 has an upper current carrying member 17' which ispositioned in contact engagement with a normally energized contact.member 18 carried by the upper end of the insulator 11'. In order toremove the upper current carrying member 17 from contact engagement withthe terminal contact member 18, the former is provided with an eye orpull ring 19 of conducting material for receivingthe prong of a liveline tool. In accordance with conventional practice, the fuse tube 16 ismanipulated by inserting the prong of the live line tool in the eye orpull ring 19 for swinging the upper current carrying member 17 into orout of contact engagement with the terminal contact member 18.

For purposes more fully disclosed in Lindell Patent No. 2,745,923,issued May 15, 1956, the terminal contact member 18incl'udes'an"L-sh'aped reinforcing bar 20 having a downwardly extending arm 21 whichcarries a guide 22. The guide 22 is employed, in part, for guiding theupper current carrying member into proper contact engagement with theterminal contact member 113. The guide 22 includes forwardly extendingarms 23 at the outer ends of which are transversely extending horns orstuds 24. Provision is made for connecting the energized line conductorto the terminal contact member 13 through a terminal pad 25. It will beunderstood that the upper portion of the terminal pad 25 (not shown)carries a connector or like device to facilitate connection of theenergized line conductor thereto.

It is often necessary to open the circuit isolating device ordisconnecting fuse 10 while it is carrying load current. When suchoperation is performed, an arc is drawn between the upper currentcarrying member 17 and the terminal contact member 18 which is likely todamage the parts which are contacted by the arc and also, where othercircuits are involved, is likely to fault one or more circuits in theevent that the arc is drawn and should jump to another circuit or theground. Also, there is the likelihood of injury to the operator. Inaccordance with the present invention, provision is made for safely andexpeditiously opening the circuit isolating device 10 while it iscarrying line current. It is for this purpose that the auxiliary circuitinterrupter, shown generally at 27, is employed. It will be observedthat it includes an eye member 28 which is rigid therewith and isarranged to engage one of the horns or studs 24. When the auxiliarycircuit interrupter 27 is so positioned, one terminal of it is connectedto the terminal contact member 18. Connection to the upper currentcarrying member 17 is provided by contact means in the form of a pinor'prong 29 rigidly mounted and extending transversely of a supportmember or strut 3!) that is preferably formed of aluminum and on whichthe auxiliary circuit interrupter 27 is flexibly mounted by a universaljoint that, generally, is shown at 31' and the details of constructionof which will be set forth hreeinafter. The support member or strut 31has an extension member 32, the lower portion of which forms a clawbracket 33 that is arranged to be secured by a clamp screw 34 to acorresponding claw bracket 35 that is formed integrally with an aluminumfitting 36 at the upper end of a live line stick 37 that is formedpreferably of wood or like insulating material. Generally the live linestick 37 is considered to include the fitting 36 and the claw bracket 35and may be so considered here.

Since the pin or prong 29 on the support member 30 loosely engages theeye or pull ring 19, it is desirable to insure that contact engagementtherewith is maintained. For this purpose a contact spring 38 is securedto the support member 36 and extends angularly outwardly therefrom forengagement with one side of the eye or pull ring 19. Since the contactspring 38 moves relatively to the pin or horn 29, it is provided with anelongated opening 39 to permit such relative movement.

As shown more clearly in Figure 2 of the drawings, the universal joint31 permits the auxiliary circuit interrupter 27 to rock with respect tothe live line stick 37 in a plane parallel to the longitudinal axis ofthe live line stick 37 for swinging the fuse tube 16 from the closed tothe open position and vice versa. Figures 3, 4 and 5 of the drawingsshow how the auxiliary circuit interrupter 27 can rock in a lane atright angles to this plane for manipulation with respect to the circuitisolating device 10 for engaging the same.

In Figure 3 of the drawings, it will be observed that the eye member 28is positioned at an obtuse angle with respect to the auxiliary circuitinterrupter 27 and is formed integrally with a contact arm 40. Thereason for positioning the eye member 28 at this angle is to facilitateits being moved into engagement with the horn or stud 24. By placing itat an angle, it is possible for the lineman to see through the openingtherein from his position at the lower end of the live line stick 37.Thus he is. able to correlate the movement of the eye member 28 with theposition of the horn or stud 24.

In some instances it is desirable to manipulate the live line stick 37with the auxiliary circuit interrupter 27 rigid therewith instead ofbeing flexibly mounted thereon. For example, when the lineman wishes toemploy the live line stick 37 solely for the purpose of performing anoperation without using the auxiliary circuit interrupter 27, it isdesirable to provide for this rigid mounting thereof. For this purpose abrace 41 is pivoted at 42 on the upper end of the support member or stud30 and it is arranged to be biased to the retracted or operativeposition by a spring 43. At its outer end the brace 41 has a bifurcatedportion 44, the arms of which fit around the contact arm 40. Thus, whenthe brace 41 is swung from the retracted position to the position shownin Figure 3, it holds the auxiliary circuit interrupter 27 in theposition here shown. As will appear hereinafter, provision is made forbiasing the auxiliary circuit interrupter 27 to the position shown inFigure 4 relative to the support member or stud 30. Accordingly theauxiliary circuit interrupter 27 is rigidly supported with respect tothe live line tool 37 when the brace 41- is swung to its position asshown in Figure 3.

The details of construction of the auxiliary circuit interrupter 27 areshown more clearly in Figures 6 and 6A of the drawings to whichreference now will be had. It will be observed that the auxiliarycircuit interrupter 27 is of elongated cylindrical construction. Itincludes a tubular insulating housing 47 that is formed of suitableinsulating material, such as a phenolic condensation product. Forpurposes of reference, the upper end of the housing 47 is referred to asthe inner end and at this inner end there is mounted a stationarycontactassembly that is shown, generally, at 48. The stationary contactassembly 48 includes a pull ring cap 49 that is formed preferably ofaluminum and with which the contact arm 40 and eye member 28 areintegrally cast. The cap 49 is secured by adhesive means to the innerend of the housing 47 and its upper end is closed by a screw plug 50.Depending from the screw plug 50 is a rigid conduct-or rod 51. The innerend of the rod 51 is secured to the screw plug 50 by a snap washer 52 onthe underside and a nut 53 on the upper side. At its outer end the rod51 has a cam terminal 54 which is provided with a latch engaging surface55, the purpose of which will be set forth presently. Depending from thecam terminal 54 are a flexible conductor 56 and a coil spring 57 coiledwith initial tension, the latter being positioned around the former asshown. The lowermost ends of the flexible conductor 56 and coil spring57 are connected to a movable first arcing contact 58 at the lowermostend of which there is an annular contact insert 59 formed of a materialwhich is resistant to erosion due to impingement of an arc thereon. Itwill be understood that the stationary contact assembly 48 includesthose parts just enumerated beginning with the pull ring cap 49 andconcluding with the annular contact insert 59.

In order to confine the are drawn from the annular contact insert 59 onoperation of the auxiliary circuit interrupter 27 to open a circuitunder load, there is provided a trailer 60 that is formed of a material,such as methylmethacrylate resin, which is adapted to evolve an arcextinguishing medium when it issubjected to the heat of an are. As willappear hereinafter, the trailer 60 is arranged to be drawn into the boreof a tube which itself gives off an arc extinguishing medium. In orderto cause the trailer 60 to move conjointly with the movable first arcingcontact 58, a trailer stud 61 is screwed into the upper end of thetrailer 60 and it extends into the movable first arcing contact 58 whereit is pivotally held by a transversely extending trailer stud pin 62.There is a limited clearance between the outer surface of the trailerstud 61 and the opening in the annular contact insert 59 and in themovable first arcing contact 58 so as to permit a limited degree ofmovement of the trailer 60 with respect thereto. This permits it to bepositioned in the bore into which it is drawn somewhat flexibly.

A tubular metallic sleeve 65, preferably formed of aluminum, is threadedat its outer end onto the movable first arcing contact 58 and it extendsupwardly into the housing 47 toward its inner end. At the inner end ofthe metallic sleeve 65, there is a trigger 66 which is pivotally mountedat 67 between arms 63 of a trigger frame stop 69. A grasshopper spring71 cooperates with the trigger 66 to bias it into latching engagementwith the inner end of the tubular metallic sleeve 65.

Secured by screws or other suitable means to the underside of thetrigger frame stop 69 is a metallic tube end insert 72 that preferablyis formed of aluminum. The insert 72 is secured by suitable means to theinner end of an inner insulating sleeve 73 that preferably is formed ofa phenolic condensation product. The inner insulating sleeve 73 isarranged to be slidably mounted within the tubular insulating housing47. It is desirable that the inner insulating sleeve 73 be guided formovement within the housing 47 so that it is non-rotatable axially withrespect thereto. For this purpose, as shown in Figure 10, longitudinallyextending slots or grooves 74 are provided in diametrically oppositepositions in the outer surface of the inner insulating sleeve 73 andtongues or pins 75 project thereinto. The tongues or pins 75 are carriedby a ring 76 that is secured to the inner surface of the housing 47 nearits outer end. The upper side of the ring 76 constitutes a stop forengaging the underside 77 of the trigger frame stop 69 for limiting theextent that the inner insulating sleeve 73 can be withdrawn from thehousing 47, this position being shown in Figure of the drawings.

It will be recalled that the metallic sleeve 65 is slidable housing 47and through the inner insulating sleeve 73. Its movement with respectthereto is limited by a stop ring 78 thatis secured to the outer surfaceof the metallic sleeve 65. The stop ring 78 is arranged to engage ashoulder 79 on the underside of the trigger frame stop 69.

The liner 80 is illustrated in Figure 13 where it will be observed thereis provided a longitudinally extending groove 81 arranged to cooperatewith a locating pin 82, Figure 6, for positioning the liner 80 in apredetermined location with respect to the inner insulating sleeve 73.It is desirable that there be a fairly snug fit between the outersurface of the liner 80 and the inner surface of the insulating sleeve73. Since provision is made for removing the liner 80, it is notpossible to secure this snug fit by cementing the liner 80 into thesleeve 73. annular grooves 83 are provided in the outer surface of theliner 80 near its end and 0 rings 84 of neoprene or like material arepositioned in these grooves to seal off the space between the liner 80and the sleeve 73 to prevent arc products from entering this space andthus preventing restriking of the arc in this space when current isbeing interrupted and a high recovery voltage is encountered.

Cooperating with the stationary contact assembly 48 is a movable contactassembly that is indicated, generally, at 87 in Figure 6A of thedrawings. It includes a metallic contact sleeve 88 that is formedpreferably of aluminum which has an extension 89 at its lower endforming a chamber 90 to receive the products of the arc. Radial vents 91serve to place the chamber 90 in communication with the atmosphere whenthe inner insulating sleeve 73 and parts associated therewith arewithdrawn from the housing 47, for example, to the position shown inFigure 8 of the drawings. Within the metallic contact sleeve 88 is aninner contact sleeve 92 which is secured in predetermined positiontherein by a contact locating screw 93. It will be understood that themetallic contact sleeve 88 is secured to the outer end of the innerinsulating sleeve 73 by suitable adhesive or other means.

As shown more clearly in Figure 14 of the drawings, the contact sleeve92 is provided with four upwardly extending flexible contact fingers 94which have contact tips for free escape of the products of the are drawnas described and to permit them to flow outwardly into the chamber 90where they can be readily vented to the at- The contact fingers 94 arebiased inwardly mosphere. by spring fingers 98. Since the trailer 60 isrequired to move through the opening defined by the flexible contactfingers 94, provision is made to limit their inward movement when not inengagement with the movable first arcing contact 58. For this purpose acontact retaining ring 99 is employed as shown in Figure 14, the size ofthe ring 99 is such that, while the contact fingers 94 are freelymovable into engagement with the periphery of the movable first arcingcontact 58, as soon as it and the annular contact insert 59 arewithdrawn, the spring fingers 98 bias the contact fingers 94 inwardlybut only to a limited extent which is determined by the contactretaining ring 99.

With a view to locating the arc incident to operation of the circuitinterrup er 7 so-that a minimum of erosion Instead of the contact tips95 takes place, the outer end of the liner 80, as shown in Figure 1 1',is provided with outflared grooves 100, each groove being individualtoone of the contact fingers 94. In-Figure' 12 of the drawings, theoutline of the grooves 100 is shown by broken lines. It will be observedthat the grooves 100 are centered with respect to the contact tips 95.Also it'will be" noted that the inner edge portions" 101 of the contacttips' 95- are machined off so that the arc is drawn or initiated at theedge of the area defined by thebroken line outline of the grooves 100from which it is repelled and moved onto the defined area by gasgenerated from the surface of the trailer 60.

Referring again to Figure 6' of the drawings, it will be observed thatthe outer end of the extension 89 is closed by& hollow lighttransmitting plug 1-03which is threaded into position. The reason foremploying a material which is light transmitting for the plug 103 is topermit the lineman to note the formation of the are drawn on separationof the first arcingcontact 58 fromthe contact tip 95 on the flexiblecontact fingers 94 which constitute a second arcing contact. By notingthe flash of the arc and its extinction, thelineman isapprised of thefact that the circuit has been completely opened and that it is safe toremove the auxiliary circuit interrupter 27 from connection-to-thecircuit isolating device Additional venting of the chamber 90 and theinterior of the plug 103 is provided by radial vents 104. A screen 105inside of the plug 103 extends over the vents 104 and over the vents 91.Thescreen 105is formed preferably of metallic material which assists incooling the are products and preventing their escape to the atmosphere.In addition, it prevents to alimiteddegree the'ingress offoreign'material.

Integral with and extending radially from the metallic contact sleeve 88is a conducting arm 106. As shown in Figure 6A of the drawings, theconducting arm 106 extends radially through a slot 107 in the outer endof the housing 47. Conducting arm 106'has a portion 108, Figure 8, thatis parallel to the housing 47 and has an H- shaped cross-section. At itsupper end the portion 108 ofthe conducting arm 106 carries a rod 109which extends through arms 110 rigid with the support member or strut30. The rod 109 permits the auxiliary circuit interrupter 27 to swing inthe plane of the drawing with respect to the support member or strut 30as shown in Figures 7 and 8. Springs 111, Figure 10, interacting betweenthe rod 109 and pins 112 mounted on the arms 110 act to bias theauxiliary circuit interrupter 27 in a clockwise direction with respectto the live line stick 37 or to bias the latter in a counterclockwisedirection with respect to the former.

In order to permit swinging movement of the auxiliary circuitinterrupter 27 in a plane at right angles to the plane of its movementabout the axis of the rod 109, a transverse shaft 113 of larger diameterthan rod 109 extends through and is journalled in the bifurcated endportion 108 of the conducting arm 106 into a pocket in the supportmember or strut 30. The rod 109 extends through and is carried by theshaft 113. A centering spring 114 surrounds the transverse shaft 113with one end 115 bearing against one side of the portion 108 of theconducting arm 106 and the other end 116 bearing against thecorresponding side of extension 32 of the support member or strut 30when the interrupter 27 is centered with respect to the live line stick37. The function of the spring 114, which is pretensioned, is to centerthe auxiliary circuit interrupter 27 with respect to the longitudinalaxis of the live line stick 37 or to bias it back to this position whenthe latter is swung relatively to the former as'shown in Figure 2 by thebroken line positions of the live line stick 37 on opposite sides of theposition shown by full lines where it is aligned with the auxiliarycircuit interrupter 27-.

It isdesirable to enclose the stationary contact assembly 48 at theinner or upper end of the tubular insulating housing 47. For thispurpose a removable insulating cap 119 extends over the inner or upperend of the housing 47 and encloses the contact assembly 48. The cap 119may be formed of neoprene or other flexible insulating material. It hasa longitudinally extending slot 120 on one side for accommodating thecontact arm 40.

When the auxiliary circuit interrupter 27 is in the fully closedposition with the inner insulating sleeve 73 telescopedtherein, thereare no exposed energized parts on the side away from the live line stick37. Aside from the fitting 36 on the live line stick 37 and the partsassociated with the support member or strut 30, the only energizedexposed parts are the eye member 28, contact arm 40 and the conductingarm 106. The insulating housing 47 and the insulating cap 119 serve toenclose all other conducting part's'which are energized when the eyemember 28 engages the horn or stud 24 of the energized terminal contactmember 18.

It is highly desirable that provision be made for quickly and easilydismantling the auxiliary circuit interrupter 27 for thepur-pose ofpermitting inspection of the parts, such as the contact 58, contactfingers 94, the trailer 60 and the liner 80; The dismantling of thecircuit interrupter 27 canbe accomplished by removing the insulating cap119', loosening the nut 53 and removing the screw plug 50. The screwsholding the trigger frame stop 69 to a metallictube-end insert 72 can beremoved and the inner insulating sleeve 73 withassociated parts then canbe removed through the outer end of the housing 47. The trailer 60then'can be removed from the inner insulating sleeve 73 together with themovable first arcing contact 58, metallic sleeve the'flexible conductor56, spring 57, cam terminal 54', and conductor rod 51. Next the plug 103is unscrewed from the extension 89 and the screen 105 is withdrawn; Onremoval of the contact locating screw' 93, the inner contact sleeve 92can be removed to permit inspection of the contact fingers 94 andcontact tips 952 The liner is next pushed out of the inner insulatingsleeve73' for inspection. The arcing contact 58 with thetubular'metallic' sleeve 65 and stop ring 78 canbe employed'for thispurpose.

In operation the lineman manipulates the live line stick 37, as shownin- Figure 4, first to a position where the eye member 28 engages theborn or stud 24. Then the live line-stick 37 is swung sidewise about theaxis of the rod 109 to position the pin or prong 29 within the eye orpull ring 19'. Contact therewith is maintained by the contact spring 38.Assuming that the circuit isolating device 10 is carrying current, thecircuit between the upper current carrying member 17 on the upper end ofthe fuse tube 16' and the energized terminal contact member 18 isshunted through the auxiliary circuit interrupter 27. Then-the linemanexerts a longitudinal downward pull on the live line stick 37 with thepin or prong 29 positioned in the eye or pull ring 19 as shown in Figure5. This initial movem'ent'causes the upper current carrying member, 17to be moved out'of engagement with the terminal contact member 18 of thecircuit isolating device 10 and the current fi'ow' formerly therethroughis transferred to the auxiliary circuit interrupter 27.

This initial movement of the live line stick 37 is accompanied'by' anoutwardmovement of the inner insulating sleeve 73 from the insulatinghousing 47. While the v rigid conductor rod 51- of the stationarycontact assembly 48 remains stationary, the other parts of the contactassembly 48 move, as shown in Figure 8. The reason for this is that thetrigger 56 is in engagementwith the inner end of the tubular metallicsleeve 65 and the trigger 66, being mounted on the trigger frame stop=69 which is attached to the metallic tube end insert: 72, moves with theinner insulating sleeve 73 along with the conducting arm 106. Theannular contact insert 59 of themovable first arcing contact 58 remainsin contact engagement with the inner ends of the flexible contactfingers 94v and 9 the contact tips 95. The flexible conductor 56 isextended as is the coil spring 57 which is stressed.

The movement of these parts continues to the position shown in Figure 8where the trigger 66 has just engaged the latch engaging surface 55 onthe cam terminal 54 and has been moved out of latching engagement withthe inner end of the tubular metallic sleeve 65. For illustrativepurposes it is pointed out that the inner insulating sleeve 73 movesthrough about from the position shown in Figure 7 to the position shownin Figure 8 of the drawings where the trigger 66 has been moved out oflatching engagement with the inner end of the metallic sleeve 65. Thisdistance is such that the gap formed between the upper current carryingmember 17 and the terminal contact member 18 at this time issufficiently great so that there is no likelihood of an arc restrikingtherebetween. As soon as the trigger 66 is actuated, the spring 57retracts the movable arcing contact 58 and the trailer 60 into the boreof the liner 80. An arc is drawn between the annular contact insert 59on the contact 58 and one of the contact tips 95 on the contact fingers94. As the trailer 60 moves through the contact tips 95 and into thebore of the liner 80, one end of the arc is confined between the outersurface of the trailer 60 and the surface of one of the outflaredgrooves 100. The other end is confined between the bevelled upper end123 of the'trailer 60 and theinner surface of the liner 80. As thecontact 58 continues to move inwardly under the influence of the coilspring 57, the arc is confined between the outer surface of the trailer60 and the inner surface of the liner 80 where it is extinguished.

Since the first arcing contact 58 substantially fills the bore in theliner 80, the products of the arc can not flow upwardly therethrough.Rather they flow downwardly past the contact tips 95 and into thechamber 90. As shown in Figure 8 of the drawings, the chamber 90 is Wellbelow the outer end of the housing 47 and as a result the products ofthe arc and the gas pressure incident thereto can be relieved throughthe vents 91 in the extension 89 and through the vents 104 in the plug103.

As shown in Figure 9 of the drawings, the first arcing contact 58 movesinwardly of the housing 47 until the stop ring 78 engages the shoulder79 on the underside of the trigger frame stop 69. For illustrativepurposes, it is pointed out that the length of this strokeis 4%". Inthis circuit open position there is still substantial tension applied bythe coil spring 57 to the movable arcing contact 58 and the same is heldin the retracted position shown in Figure 9.

While the extent of movement of the live line stick 37 thus described issufficient to effect opening of the circuit through the interrupter 27,a further movement of the live line stick 37 is possible and desirablein order to provide a greater separation between the contact 58 and thecontact fingers 94. In the embodiment of the invention disclosed, thisfurther movement is of the order of 3%" to the position shown in Figure10. The spring 57 is further tensioned until the ring 76 engages theunderside 77 of the trigger frame stop 69. By providing for this furthertravel and tensioning of the spring 57 abrupt stopping of the live linestick is avoided and severe shock to the interrupter 27 is obviated.

The live line stick 37 then is manipulated so as to disengage the pin orprong 29 from the eye or pull ring 19. The fuse tube 16 then swingsdownwardly under the infiuence of gravity to the open position. Then thelive line stick 37 is moved upwardly to lift the eye member 23 off ofthe horn or stud 24. Afterwards the auxiliary circuit interrupter 27 canbe manually restored to the closed position shown in Figures 6 and 7 bymoving the inner insulating sleeve 73 inwardly of the tubular housing 47until the trigger 66 again is in position where it engages the inner endof the metallic sleeve 65. The spring 57 goes solid and acts as a strutto transmit compressive force therethrough to cause contact 58 to engagethe con- 10 tact fingers 94. In. that position the annular Contactinsert 59 on the first arcing contact 58 is telescoped with the innerends of the contact fingers 94 and the contact tips 95 thereon.

In the event that some obstruction should prevent the first arcingcontact 58 and the trailer 60 from moving from their positions shown inFigure 8 to the open circuit position shown in Figure 9 under theinfluence of the spring 57, there is still a margin of movement of theinner insulaing sleeve 73 which will effect the separation of thecontacts and the opening of the circuit even though the spring 57 isineffective to do so. In Figure 8 of the drawings, it will be observedthat there is still some distance between the shoulder 77 on themetallic tube end insert 72 and the ring 76. As shown in Figure 10 andas described hereinbefore, the outward movement of the inner insulatingsleeve 73 is limited by the ring 76 engaging the underside 77 of thetrigger frame stop 69. This further extent of movement is of the orderof 2 /2" in a particular embodiment and is suificient to disengage andwithdraw the movable contact assembly 87 sufficiently far away from thefirst arcing contact 58, which is held against movement by the flexibleconductor 56 that goes taut under these circumstances, to open thecircuit and extinguish the arc. The inner insulating sleeve 73 movesdownwardly together with the liner and movable contact assembly while,as stated, the arcing contact 58 re mains stationary. The are is drawnand extinguished then in the bore of the liner 80 as above described.

In the event that it is not desired to depend on the flexible conductor56 for holding the contact 58 stationary, reliance can be placed on aring 122, Figure 6, secured to the inner end of the metallic sleeve 65.The inner periphery of this ring 122 projects over the cam terminal 54sufficiently far that the latter will not pass through the former. Themetallic sleeve 65 then is held stationary and, since it is threaded onthe contact 58, it holds its stationary also.

The flexible conductor 56 can be omitted if sufficient contactengagement between the inner surface of the metallic sleeve 65 and thecam terminal 54 is provided as a conducting path for current flow. Thelatter can be provided with contact fingers to provide additionalengagement with the former to increase the current carrying capacity.The spring 57 can be formed of relatively good conducting material, suchas berryllium, copper, to carry the current during the interruptingoperation.

By reversing the foregoing described sequence of opera tions, it ispossible to close the circuit isolating device 10. In such case theinterrupter is operated first to the open circuit position and then isapplied to the device 10 also in the open circuit position. Then theinterrupter is closed and next the device 10 is operated to the closedposition. Finally the interrupter 27 is removed from the device 10 afterservice has been restored.

Since certain changes can be made in the foregoing construction anddifferent embodiments of the invention can be made without departingfrom the spirit and scope thereof, it is intended that all matters shownin the accompanying drawings and described hereinbefore shall beinterpreted as illustrative and not in a limiting sense.

What is claimed as new is:

1. In combination, a circuit isolating device, such as a disconnectingfuse, disconnecting switch or the like, having upper and lower terminalmembers in insulated spaced relation and an elongated conducting memberpivoted at one end to said lower terminal member and carrying at theother end contact means engageable with a part of said'upper terminalmember for completing the circuit between said terminal members andpermitting opening of the same by separation thereof, pull ring means onsaid conducting member below said part of said upper terminal member for'detachably receiving one terminal of an auxiliary circuit interrupter,and a conducting arm carried at its inner end by said upper terminalmember no further away from the pivot of said elongated conductingmemher than said part of said upper terminal member and extendinggenerally normal to the plane of swinging movement of said conductingmember with its outer end terminating alongside said contact means fordetachably receiving over said outer end another terminal of theauxiliary circuit interrupter.

2. In'combination, a circuit isolating-device, such as a disconnectingfuse, disconnecting switch or the like, having upper and lower terminalmembers in insulatedspaced relation and an elongated conducting memberpivoted at one end to said lower terminal member and carrying at theother end contact means engageable with a part of said upper terminalmember for completing the circuit between said terminal members andpermitting opening of the same by separation thereof, pull ring means onsaid conducting member below said part of said upper terminal member fordetachably receiving one terminal of an auxiliary circuit interrupter,and a conducting arm carried at its inner end by said upper terminalmemberbetween said part and said pull ring means and extending generallynormal to the plane of swinging movement of said conducting member withits outer end terminating alongside said contact means fordetachably'receiving over said outer end another terminal of theauxiliary circuit interrupter, said conducting arm having its outer endportion curved away from the direction of opening movement of saidconducting member to reduce the likelihood of said other terminal ofsaid auxiliary circuit interrupter slipping off of the same.

3. In combination, a circuit isolating device, such as a disconnectingfuse, disconnecting switch or the like, having upper and lower terminalmembers in insulated spaced relation and an elongated conducting memberpivoted at one end to said lower terminal member and carrying at theother end contact means engageable witha part of said upper terminalmember for completing the circuit between said terminal members andpermitting opening of the same by separation thereof, pull ring means onsaid conducting member below said part of said upper terminal member fordetachably receiving one terminal of an auxiliary circuit interrupter,and a generally V-shaped guide member of conducting material having itscentral portion secured to said upper terminal member and having armsextending forwardly on oposite sides of said conducting member generallyin thedirection of opening movement thereof with the outer ends of saidarms terminating along opposite sides of said contact means and beingcurved rearwardly for detachably receiving over said outer ends oneither side of said conducting member another terminal of the auxiliarycircuit interrupter.

4. A circuit interrupter comprising, in combination, upper and lowerline terminal members adapted to be held in fixed insulated spacedrelation, a fuse tube adapted to receivev a fuse link and pivotallymounted at its lower end to swinginto and out ofengagement with saidterminal members and to be latched at its upper end, and a generallyZ-shaped conducting member substantially rigid throughout its entiretywith one end portion rigidly secured to said upper line terminal member,the intermediate portion extending downwardly along said fuse tube, andthe other end portion extending outwardly past said fuse tube in closedposition for receiving one terminal of an auxiliary circuit interrupterfor shunting said upper line member and a terminal at the upper end ofsaid fust tube to permit separation of the same without arcing, saidother end portion of said Z-shaped conducting member constituting ananchor for said one terminal of said auxiliary circuit interrupter andacting tohold the same stationary on application of a pull thereto bysaid auxiliary circuit interrupter.

5. A circuit interrupter comprising, in combination, upper and lowerline terminal members adapted to be central portion rigidly secured tothe lower end of said intermediate portion and the arms thereofextending outwardly in flared apart relation past said fuse tube inclosed position for receiving on either arm one terminal of an auxiliarycircuit interrupter for shunting said upper line terminal member and aterminal at the upper end of said fuse tube to permit separation of thesame Without arcing, either of said arms constituting an anchor for saidone terminal of said auxiliary circuit interrupter and acting to holdthe same stationary on application of a pull thereto by said auxiliarycircuit interrupter.

6. A circuit interrupter comprising, in combination, line terminalmembers in fixed insulated spaced relation; an elongated conductingmember pivoted at one end to one of said line terminal members andcarrying at the other end contact means engageable with a part of theother line terminal member for completing a circuit between said lineterminal members and permitting opening of the same by separationthereof, a generally Z-shaped conducting member substantially rigidthroughout its entirety with one end portion rigidly secured to saidother line terminal member, the intermediate portion extendingdownwardly along said conducting member, and the other end portionextending outwardly past said conducting member for receiving oneterminal of an auxiliary circuit interrupter for shunting said part onsaid other line terminal member and said contact means to permitseparation of the same without arcing, said other end portion of saidZ-shaped conducting member constituting an anchor for said one terminalof said auxiliary circuit interrupter and acting to hold the samestationary on application of a pull thereto by said auxiliary circuitinterrupter.

7. A circuit interrupter comprising, in combination, line terminalmembers in fixed insulated spaced relation, an elongated conductingmember pivoted at one end to one of said line terminal members andcarrying at the other end contact means engageable with a part of theother line terminal member for completing a circuit between said lineterminal members and permitting opening of the same by separationthereof, a generally Z-shaped conducting member substantially rigidthroughout its entirety with one end portion rigidly secured to saidother line terminal member, the intermediate portion extending,downwardly along said conducting member, and the other end portion beinggenerally U-shaped with the central portion rigidly secured to the lowerend of said intermediate portion and the arms thereof extendingoutwardly in flared apart relation past said conducting member forreceiving on either arm one terminal of an auxiliary circuit interrupterfor shunting said part on said other line terminal member and saidcontact means to permit separation of the same without arcing, either ofsaid arms constituting an anchor for said one terminal of said auxiliarycircuit interrupter and acting to hold the same stationary onapplication of a pull thereto by said auxiliary circuit lnterrupter.

References Cited in the file of this patent UNITED STATES PATENTS444,019 Richards Jan. 6, 1891 1,910,022 Legg May 23, 1933 1,953,807Jackson et al Apr. 3, 1934 2,555,158 Schultz May 29, 1951 2,665,415Kojis Jan. 5, 1954

